G.
I have one of those tire machines.
I cant really tell from the picture.....but I think the one I use is a a little bit more heavy duty. (I could be wrong.
)
I does work ok for breaking down beads...especially on rims that have a shallow well.
It also helps on the smaller b*stard rims (3"-4") (The small ones can be the toughest.) Sometimes if you can clamp a vise grip on the rim...you can "pull" and "turn" the tire onto the rim.
As far as using the "mounting bar thing" , I seldom use it...it just doesnt work that great on most tires and rims. (I wind up using screwdrives and WD, even when its mounted in the tire machine.)
There is no "easy" way too do tires. Some times you get lucky...and they are a piece of cake. Most of the time....they are just wrestling matches.
The 6" and 8" sizes that you are dealing with...are
usually the easiest.
Why not just try the screwdrivers first? If you bend the lip of the rim you can bend them back with some vise grips. (Just dont go nuts with the bending.)
Many tire stores will mount tires for ope. (Around here they do.)
We get lots and lots of tires half mounted on rims....give it a try and if you succeed...good for you...
If you dont.....oh well...you wont be the first.
Good luck.
The Buck